Thrasycles Clarke was christened 18th September 1789 at Maghull, Lancashire, the son of Thrasycles (also known as Tracy) and Eleanor (nee Banks) Clarke.
Tracy Clarke was a country doctor.
Thrasycles' brothers were
John Edward christened 5 November 1786,
Adam christened 26 March 1788,
William Augustus Frederick who was born 1 January 1792,
Edward Stainslaus Augustus was born 22 September 1793,
Erasmus born 18 June 1795. 
The six brothers were nephews of Wesleyan preacher and theological writer Rev. Adam Clarke who was born about 1762 at Moygbeg, Kilcronaghan Co. Londonderry. The Clarkes on their maternal side were of a family which at one time had held extensive estates in the north of Ireland. 
Death of Tracy Clarke
In 1803 Tracy Clarke (father of Thrasycles Clark RN) passed away and his brother the Rev. Adam Clarke felt the death of his only beloved brother keenly. .....The duties of a medical man in a small town or village are always arduous; but at the period we are now speaking of, they were more especially so, when the study of the healing art was much more limited, and its practitioners but comparatively few in number. Mr. Tracy Clarke being naturally of an extremely urbane character, and of kind and elegant manners, and being also deservedly held in high repute for his medical knowledge and skill, his practice was very great, and widely extended. After all the ordinary labors of the day, he has frequently been called up for five successive nights, and had often to ride on horseback many miles, alike exposed to the night air, cold, or tempest; for this severe labor he was not constitutionally fitted; not naturally strong, his health soon became impaired, and, in the end, symptoms of decided consumption too plainly proved that his life would fall a sacrifice to the hardships to which it was exposed. Mr. Tracy Clarke died at Maghull, near Liverpool, in the forty-fifth year of his age; but his memory still lives in the respect and esteem alike of the rich and the poor throughout the neighbourhood
Appointed Surgeon Superintendent
Thrasycles Clarke was included in the Navy List of Medical Officers of 1814. He was about 42 years of age when he was employed as surgeon superintendent on the convict ship Kains in 1831.
He seemed disconcerted at the large number of young women who were in his charge and while not surprised at their behaviour is perhaps nevertheless shocked by it.
This was his only voyage on a female convict transport and he had probably been gently reared. His beloved uncle whom he attended on his death bed was the Rev. Adam Clarke. Thrascycles Clarke described the women of the Kains in his journal - the general character and conduct of the prisoners were such as might be expected from the lowest class of society - from persons whom all the wise and salutary laws of England had failed to reclaim, most immoral and abandoned, if there ever was a Hell afloat it must have been in the shape of a female convict ship, quarrelling, fighting, thieving, destroying in private each other's property for a mean spirit of devilishness - conversation with each other most abandoned without feeling or shame. As regarded the personal cleanliness of the prisoners that in some measure depended on their natural disposition, education and attitude, some of them by nature and habit were cleanly while others were filthy to the 90th degree.
Death of Adam Clarke
Not very long after he returned to England after this voyage, he was called to the bedside of his dying uncle the Rev. Adam Clarke. He is mentioned in a publication about his Adam Clarke...... written in 1833........
The unusual circumstance of Dr. Clarke's sending for Mr. Hobbs, alarmed Mrs. Hobbs, who went down shortly after, as did also Miss Hobbs and Miss Everingham, the servant having communicated to these ladies Dr. Clarke's indisposition. By this time Dr. Clarke had sunk into a chair, and finding him very cold they had got a fire, and the three ladies were rubbing his forehead and hands, while Mr. Hobbs made his man get into the gig and bring a medical gentleman, a friend of the family, Mr. Chas. Greenly, of Chatham, who chanced to have come to town on the preceding evening, and who had professionally attended the cholera hospital in that place: in the meantime Mr. Hobbs had called in a medical man in the neighbourhood, and sent off to inform his sons of their father's illness. Mr. Theodoret Clarke arrived shortly, and Mr. John Clarke not long after, accompanied by Dr. Clarke's nephew, Mr. Thrasycles Clarke, who has been for many years a surgeon in his majesty's navy, and frequently seen cases of the cholera in the east. As soon as the medical gentlemen saw Dr. Clarke they instantly pronounced the disease to be an attack of cholera: the family wished him to be taken up stairs, but he was by this time so weak, that it was found he could not get up, and a small press bed being in the adjoining room, he was conveyed there and laid down upon it. Mr. Hobbs then remarked, 'My dear doctor, you must put your soul into the hands of your God, and your trust in the merits of your Saviour,' to which observation Dr. Clarke could only faintly reply, ' I do, I do.''An Account Of The Infancy, Religious and Literary of Adam Clarke LLD., F.A.S.'
 National Dictionary of Biography
 Journal of Thrasycles Clarke - Ancestry.com. UK, Royal Navy Medical Journals, 1817-1857 . The National Archives. Kew, Richmond, Surrey.